Servo controlled systems which affect the psychophysical state of passengers are increasingly employed in modern, top range cars; the most common among such servo controlled systems is the climate control system, which is capable of automatically operating for guaranteeing the temperature required by the passengers inside the passenger compartment. Another example of such servo controlled systems is the internal rear-view mirror provided with an anti-dazzle function to automatically reduce the amount of reflected light in case of strong rear light. A further example of such servo controlled systems is the servo controlled adjustment of the position, the configuration, or the temperature of seats.
Normally, a servo controlled system in a car has a control device, by means of which the user (i.e., the driver or a passenger) sends his or her needs to the servo controlled system itself (e.g., the desired temperature in case of the climate control system); subsequently, the servo controlled system tries to respond to the user's needs either with an open loop control logic (in the case of simpler and/or less sophisticated servo controlled systems) or with a closed loop or feedback control logic (in the case of more complex and/or more sophisticated servo controlled systems).
In the case of a closed loop or feedback control logic, at least one measurable physical feedback quantity is identified, which is either directly or indirectly correlatable with a need expressed by the user (e.g., the temperature inside the passenger compartment and/or the humidity inside the passenger compartment in the case of the climate control system). In use, according to the need expressed by the user, a desired optimal value of the physical feedback quantity (either fixed or variable in time) is determined and the servo controlled system is driven to seek such desired optimal value; i.e., the servo controlled system is driven so that the real measured value of the physical feedback quantity is equal to the desired optimal value.
A major limitation of the above-described closed loop or feedback control logic is that often the user is not able to correctly express his or her needs and thus the servo controlled system determines and seeks a desired optimal value which actually does not correspond to the user's real but poorly expressed needs. In a practical example applied to the climate control system, the user's real need is to feel comfortable, i.e., not to perceive any discomfort (heat, cold, excessive humidity, excessively dry air, stale air, unpleasant odors) deriving from the climate inside the passenger compartment, but often he or she is able to correctly express this need only in very vague terms (e.g., I'm hot, I'm cold, I am not comfortable) and is hardly ever able to correctly translate such a need into a numeric value of a physical feedback quantity (i.e., how many temperature degrees and what percentage of humidity).
Furthermore, in the case of a complex servo controlled system, i.e., provided with several servo controls, it is possible to perform various actions which are reciprocally coordinated in order to obtain a final effect targeted to an average user who could be very different from the actual user. For example, in the case of a climate control system, it is possible to adjust the air temperature, to adjust the air humidity, to adjust the air introduction flow rate, to adjust the number and position of the air outlet vents and to adjust the percentage of air recirculation; in summer, an average user may find a flow of cool air directed towards his or her legs beneficial, but the actual user may suffer from arthrosis and thus be unable to stand such a flow of cool air directed towards his or her legs.
U.S. Pat. No. 5,187,943A1, which is incorporated by reference, discloses a control apparatus for an air-conditioner of a vehicle; the temperature and the velocity of air blown from an air-conditioner are controlled in such a manner that a temperature sensation value expressed by a mathematical formula becomes a targeted temperature sensation value by using facial skin temperature and a rate of change in the facial skin temperature.
U.S. Pat. No. 6,202,934B1, which is incorporated by reference, discloses an air conditioner for a vehicle which accurately estimates a thermal load to enhance inside temperature controllability. The air conditioner comprises a first surface temperature sensor for detecting a temperature of an internal surface region of a vehicle compartment which varies with a temperature of an external surface of a vehicle, and a second surface temperature sensor for detecting a temperature of a surface region which varies with an intensity of solar radiation intruding into the vehicle compartment.